Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D15/00—Shearing machines or shearing devices cutting by blades which move parallel to themselves
  • B23D15/12—Shearing machines or shearing devices cutting by blades which move parallel to themselves characterised by drives or gearings therefor
  • B23D15/14—Shearing machines or shearing devices cutting by blades which move parallel to themselves characterised by drives or gearings therefor actuated by fluid or gas pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D33/00—Accessories for shearing machines or shearing devices
  • B23D33/08—Press-pads; Counter-bases; Hold-down devices

Definitions

• the invention relates to sheet metal shears for large cutting lengths with an upper knife which can be moved up and down relative to an undercutter fixedly arranged on a scissor bed, for the cutting and retracting drive of which two double-acting hydraulic hydraulic cylinders connected in series are provided, and with the further generic features mentioned in the preamble of claim 1.
• Tin snips of this type are generally known and are e.g. used for cutting sheet metal sheets from a sheet metal sheet drawn substantially horizontally from a coil, from which the sheets are to be cut to suitable dimensions with their transport into further processing.
• a main control valve which is pressure-controlled by means of an electrically controllable pilot valve is provided, which in its alternative functional positions releases the flow path combination required for the respectively controlled direction of movement.
• hold-down devices designed as single-acting linear cylinders are provided, which are distributed over the cutting length in the area of the fixed lower knife and are distributed over its length above the scissor bed, and the sheet metal sheet is securely attached to it before the upper knife cuts the sheet.
• a constant pump activated during operation of the sheet metal shears is provided, the output pressure of which is limited to an adjustable maximum value of, for example, 250 bar by a pressure relief valve.
• the hold-down devices are first put on.
• the drive hydraulic cylinders are then controlled by means of the pressure-controlled, electrically pilot-controlled main control valve for executing the feed and cutting stroke of the upper knife.
• the main control valve is controlled into a blocking position in which the drive hydraulic cylinders of the upper knife are, as it were, hydraulically blocked.
• the drive pressure chambers of the hold-down devices are relieved of pressure, again electrically controlled or pre-controlled, the pistons of which are raised to their basic positions by the action of return springs of the hold-down devices, in which the hold-down devices are lifted off the sheet metal strip.
• the main control valve is switched to its functional position assigned to the upward retraction operation of the upper knife and, as soon as the upper end position of the upper knife has been reached, in the delivery of the next Sheet metal stiffener section to the sheet metal shears, with a limit switch being provided to detect this TDC position, switched to its blocking position, in which the drive hydraulic cylinders of the upper knife are again hydraulically blocked.
• This associated with the shutdown of the hydraulic drives functional position of the main control valve is maintained until it is ensured that the sheet metal in the suitable position for the next cutting cycle, which is then initiated by electrical control of the pilot valve.
• the object of the invention is therefore to improve sheet metal shears of the type mentioned at the outset in such a way that they enable operation with significantly reduced cutting cycle times while at the same time reducing noise.
• claims 2 to 5 expedient constructive designs of the main control valve of the sheet metal shears control are specified, by means of which a sequence control means that the main control valve can only reach its functional position assigned to the feed and cutting operation after the Hold-down devices are created.
• the arrangement of the copy stop provided according to claim 6 is structurally simple and functionally reliable.
• the design of the electrohydraulic control unit of the scissors drive provided in accordance with claim 7 ensures that a pressure sufficient for fixing the sheet metal web can be coupled into the hold-down device.
• claims 8 and 9 ensure that the hold-down devices are applied before the upper knife can carry out its cutting stroke.
• an inlet valve provided and designed according to claim 10 which can be designed according to the features of claim 11 as a pressure-controlled valve, and / or an outlet valve provided and designed according to claim 12, designed according to the features of claim 13 as a simple pressure-controlled valve can be, a quick application of the hold-down devices using the hydraulic energy stored in the pressure accumulator and a rapid relief of the hold-down devices is possible.
• the design of the outlet valve according to claim 14 has the advantage that a pressure higher than the storage pressure can also be coupled into the hold-down device, the pressure that can be coupled into the hold-down device being expediently limited by a pressure reducing valve.
• the accumulator-charging valve arrangement required for charging the pressure accumulator is designed according to claim 16 as a pressure-controlled valve arrangement, which comprises a changeover valve, by means of which the constant pump can be switched from charging mode to circulating mode, and an auxiliary valve, by means of which a relief control path can be released and released. is lockable, the release of which is a prerequisite for charging.
• this auxiliary valve is integrated in the main control valve, for which a simple type of constructive implementation is indicated by the features of claim 18.
• a surface switching valve which is provided and designed in accordance with the features of claim 19 enables an expansion of the feed force range with which the sheet metal shears can be operated and thus increases their possible uses.
• the pilot valve can also be used for controlling a slow downward movement of the upper knife and for discharging the pressure accumulator at the end of a long-term operation of the sheet metal shears.
• the preparation of the sheet metal shears for the cutting operation takes place by setting a cutting angle of the upper knife according to claim 21 by means of a control valve arrangement using the pressure accumulator in the copying position of the main control valve.
• FIG. 1a shows a schematically simplified overall view of a hydraulically driven metal shear according to the invention
• FIG. 1b shows a schematically simplified side view of the sheet metal shears according to FIG. 1a;
• FIG. 2 shows a hydraulic circuit diagram of the drive device of the sheet metal shears according to FIGS. 1a and 1b;
• 3 a shows the functional positions of the piston of a main control valve of the drive device according to FIG. 2 associated with the retracting operation of the upper blade of the sheet metal shears up to 3 c, the loading mode of a pressure accumulator of the drive device and the cutting mode of the scissors;
• Fig. 4 shows details of an accumulator loading valve arrangement
• Fig. 5 details of an inlet valve for pressurizing hold-down cylinders of the shears
• Fig. 5b details of an exhaust valve provided for pressure relief of the hold-down cylinder.
• each designated overall with 10 sheet metal shears is generally intended for use in the sheet metal processing industry to a strip-shaped sheet metal, the z. B. has a thickness in the mm range to cut into rectangular sheets of defined length and width.
• Such shear 10 can cut to a "large" length of several meters, for. B. 4 m can be designed, which corresponds to a maximum length of the metal sheets to be cut, the width of which is set by the transport path by which the sheet metal sheet 11 is shifted from cut to cut at right angles to the cutting plane 12.
• the sheet-metal shears 10 comprise a scissor-type frame designated as a whole with 13 with a lower knife 14 fixedly mounted thereon with a horizontally running free cutting edge 16 and with an upper knife 17 movable up and down on the scissor-type frame 13, the rectilinear cutting edge 18 of which is one with the cutting edge 16 of the lower knife adjustable cutting angle ⁇ , which, depending on the thickness of the sheet 11, between a minimum value of 0.5 ° and a maximum value of 3 ° can be changed, with increasing thicknesses of the sheet metal webs to be subjected to the cutting also corresponding to increasing amounts of the cutting angle ⁇ .
• the scissor-type frame 13 comprises a scissor-type bed, designated overall by 19, which forms the horizontal support for the sheet-metal web 11 to be subjected to the cutting processing.
• the scissor bed 19 extends between stable guide columns 22 and 23, which are arranged symmetrically with respect to the vertical longitudinal center plane 21 of the sheet metal shears 10 and are designed to be subjected to tensile stress in the cutting operation and are firmly connected to the scissor bed 19.
• a rigid cross member 24 which is firmly connected to them and which complements the scissor bed 19 and the columns 22 and 23 described so far to form a self-contained, basic, rectangular frame which is suitable is to absorb the reaction forces occurring in the cutting operation without experiencing any noteworthy deformations.
• the scissor bed 19 is firmly anchored to the floor of the workshop via a foot part 26.
• the traverse 24 is, on the one hand, the carrier for two linear double-acting hydraulic drive cylinders 27 and 28, by means of which the upper knife 17 executes its cutting movement into a bottom dead center thereof and for executing a retraction movement into a top dead center of the knives Position can be driven, and on the other hand also the carrier for a plurality of hold-down cylinders 29, by means of which the sheet metal web 11 can be pressed against the scissor bed 19 in the region of the lower knife 14 in preparation for the cutting process and securing the sheet metal web position during the cutting process, with its support level 31 the Cutting edge 16 of the lower knife 14 is coplanar, which forms the "free" end of the scissor bed 19, as it were.
• the hold-down cylinders 29 are designed as single-acting linear hydraulic cylinders, which are arranged approximately equidistantly distributed over the cutting length between the guide columns 22 and 23 of the scissor bed 19, the distance between adjacent hold-down cylinders 29 having a typical value of around 0.4 m .
• the hold-down cylinders 29 each have a piston rod 33 which emerges from the cylinder housing 32 downwards on one side and which, when pressure is coupled into the drive pressure chamber 34 (FIG. 2) arranged on the bottom, of the hold-down cylinder 29 can be extended downwards against the restoring force of a piston spring 36 and thereby with a support foot 37 on the sheet metal sheet 11 into which the sheet metal sheet can be non-positively held on the scissor bed 19.
• the drive pressure chamber 34 of the respective hold-down cylinder 29 is relieved of pressure, the hold-down piston 38 is returned to its upper end position by the piston spring, in which the preload of the piston spring 36 is still equivalent to a pressure of approximately 5 bar.
• the piston spring 36 is designed as a "weak" spring, the restoring force of which between the value given in the upper end position of the hold-down piston 38 and the maximum possible value given in the lower end position, the pressing position of the hold-down piston 38, is only a little, eg. B. varies by 50%, the restoring force of the piston spring is small in any case against the force that can be exerted by pressurizing the drive pressure chamber 34 of the respective hold-down cylinder 29 on the hold-down piston 38 for pressing the sheet metal web 11 against the scissor bed 19.
• the linear hydraulic drive cylinders 27 and 28 provided for driving the upper knife 17 are designed as double-acting cylinders which are mounted on the cross member 24 in a "hanging" arrangement with speaking the direction of movement of the upper knife vertical course of their central longitudinal axes 39 and 41.
• the drive hydraulic cylinders 27 and 28 are designed as differential cylinders of different geometrical dimensions, but designed so that they are each effective in the area of the knife ends adjacent to the guide columns 22 and 23 Can develop feed or retraction forces.
• the two drive hydraulic cylinders 27 and 28 have, with their drive cylinder pistons 42 and 43, permanently connected piston rods 44 and 46, which emerge downward from the housing 47 and 48 of the respective drive hydraulic cylinder 27 and 28 and with the upper knife 17th are articulated.
• An upper, bottom-side drive pressure chamber 49 or 51 is delimited by the respective drive cylinder piston 42 or 43 within the respective drive hydraulic cylinder 27 or 28 against a lower, rod-side drive pressure chamber 52 or 53 of the respective drive hydraulic cylinder 27 or 28 , so that the downward movement of the upper knife 17 and its cutting operation can be controlled by pressurizing the upper, bottom-side drive pressure chambers 49 and 51 of the two drive hydraulic cylinders 27 and 28 and by pressurizing the lower, rod-side drive pressure chambers 52 and 53 of the drive hydraulic cylinders 27 and 28 the upward retraction movements of the upper knife 17 are controllable, which lead back to its top dead center (TDC) position, from which a subsequent cutting process can be started.
• TDC top dead center
• the two hydraulic drive cylinders 27 and 28 are each arranged in the immediate vicinity of the guide columns 22 and 23, on which the upper knife 17 is guided vertically up and down with sliding guide pieces 54 and 56. These sliding guide pieces 55 and 56 ensure that the cutting edge 18 of the upper knife 17 is only in the cutting plane 12 can move, which is arranged from the cutting edge 16 of the lower knife 14 at a small distance which corresponds to a knife gap suitable for a good quality cut.
• the upper knife 17 of the sheet metal shears 10 is interchangeably arranged on a stable upper knife carrier 57, which is connected to the piston rods 44 and 46 of the two drive hydraulic cylinders 27 and 28 via a swivel joint, the joint axes 58 and 59 (FIG. 2) of which are at right angles the cutting edges of the upper knife 17 and the lower knife 14.
• the swivel joints represented by the articulation axes 58 and 59 allow the setting of small cutting angles ⁇ between 0.5 and a maximum of 3 °, which are expediently set so that the metal shears 10 can be operated with comparatively low cutting forces, which are in the 10 kN to 100 kN Range.
• the two drive hydraulic cylinders 27 and 28, on the piston rods 44 and 46 of which the upper knife carrier 57 of the upper knife 17 are arranged as it were suspended, are hydraulically connected in series and are designed in such a way that the feed forces deployed on the upper knife 17 in the cutting operation are symmetrical to the longitudinal center plane 21 of the sheet metal shears 10, the amounts of which are the same, this also taking into account the weight proportions of the upper knife carrier 57, which are effective in the cutting feed direction of the upper knife 17.
• the hydraulic series connection of the two drive hydraulic cylinders 27 and 28 is realized in such a way that the rod-side drive pressure chamber 52 of the one, according to the illustration in FIG. 1a, the left hydraulic drive cylinder 27, which is realized with larger cross-sectional dimensions of its drive cylinder piston 42 and the effective piston surfaces, connected to the bottom-side drive pressure chamber 51 of the "right" hydraulic cylinder 28, which has smaller cross-sectional dimensions, via a "rocking oil" line 61 over the hydraulic oil, which is displaced from the rod-side drive pressure chamber 52 when the drive cylinder piston 42 of the left drive hydraulic cylinder 27 moves downward, into the bottom-side drive pressure chamber 51 of the right, smaller drive hydraulic cylinder 28 and thereby controlled volumetrically , the downward movement of the drive cylinder piston 43 of the smaller hydraulic cylinder 28 can mediate.
• a whole Pressure supply unit (Fig. 2) is provided, which consists of an electrically driven constant pump 63, which can generate high output pressures, and a pressure relief valve 64, which the maximum output pressure of the pressure supply unit 62 to an adjustable value, z. B. limited to a value of 250 bar.
• hydraulic oil displaced from the rod-side drive pressure chamber 53 of the smaller hydraulic cylinder 28 is, depending on the load, either added to the hydraulic oil flow, which is used to control rapid feed operation into the bottom-side drive pressure chamber 49 of the larger one Drive hydraulic cylinder 27 is fed, or, in a load feed operation, in which large cutting forces have to be developed, drained into the unpressurized reservoir of the pressure supply unit 62, with in this operating state the plate shears 10 the differential operation of the two series-connected drive -Hydro cylinder 27 and 28 is lifted and these can develop their maximum feed forces.
• the output oil flow of the constant pump 63 is coupled into the rod-side drive pressure chamber 53 of the smaller drive hydraulic cylinder 28, from the latter bottom-side drive pressure chamber 51, the hydraulic oil flows via the rocking oil line 61 to the rod-side drive pressure chamber 52 of the larger drive hydraulic cylinder 27, the bottom-side drive pressure chamber 49 of which is communicatively connected to the unpressurized reservoir 66 of the pressure supply unit 62 in this operating state.
• the piston surface 69 axially movably delimiting the bottom drive pressure chamber 49 of the larger drive hydraulic cylinder 27 has an amount F ⁇ which corresponds approximately to twice the amount of the annular surface 67 of this drive cylinder piston 42 and three times the value the annular surface 71 (F 3 ), which forms the axially movable boundary of the rod-side drive pressure chamber 53 of the smaller drive cylinder 28 of the scissor drive.
• an electro-hydraulic control unit designated as a whole in FIG. 2, is provided, for the explanation of which goes into more detail also 3a to 3c, FIG. 4 and FIGS. 5a and 5b are referred to.
• the electrohydraulic control unit 72 comprises, as a "central" control element, a main control valve, designated overall by 73, by means of which the upward and downward movement phases of the upper knife 17 of the metal shears 10 and position-controlled standstill phases of the upper knife 17 in the TDC positions of the pistons 42 and 43 of the two Drive hydraulic cylinders 27 and 28 are controllable.
• the main control valve 73 is designed as a “linear” slide valve, which is arranged “standing” in the exemplary embodiment chosen for the explanation, such that the central longitudinal axis 74 of the main control valve 73, vertically, ie. H. runs parallel to the central longitudinal axes 39 and 41 of the drive hydraulic cylinders 27 and 28.
• the piston of the main control valve 73 can be moved up and down within the valve housing designated overall by 77 between a lower end position shown in FIG. 3a and an upper end position shown in FIG. 3c, the two end positions are marked by a stop action of the main control valve piston 76 with a lower housing end part 78 or an upper housing end part 79, between which a "middle" housing block 81 extends, on which the supply connections for the connection of the main control valve 73 to the pressure supply unit 62, the consumer connections for the movement control of the drive hydraulic cylinders 27 and 28 and control connections for the function control of the main control valve 73 are arranged.
• the main control valve 73 is designed as a pressure-controlled valve which, essentially, can be controlled by the pressure prevailing in a lower control chamber 82 of the main control valve 73, which is also electrical via an electrically controllable pilot valve 83 and a pilot valve 83 connected between the latter and the main control valve 73 controlled switching valve 84 and an x control connection 86 can be coupled into the lower control chamber 82.
• a pressure is permanently coupled into an upper control chamber 87 of the main control valve 73, which is arranged within the upper housing end part 79, to which a pressure accumulator 88 is currently charged, which at the beginning of a renewed cycle, as it were, as an auxiliary pressure source for a rapid Applying the hold-down cylinder 29 is provided for securely fixing the sheet metal web 11 to the scissor bed 19. Due to the storage pressure p s , which is, as it were, permanently coupled into the upper control chamber 87, a force is exerted on the piston 76 of the main control valve 73 in the direction of the lower end position shown in FIG. 3a, the amount K R of which is determined by the relationship
• a 1 denotes the effective cross-sectional area of an actuating plunger 89 axially supported on the main control valve piston 76, which acts centrally on an upper end flange 91 of the main control valve piston 76.
• an annular control surface 92 is designated by A 2 , through which a lower, cylindrical end portion 93 against a somewhat smaller piston-shaped piston extension 94 is offset, which, projecting downward from the lower housing end part 78, is guided in an axial through bore 96 of the same, so that it can be moved in a pressure-tight manner.
• the annular, lower control surface 12 of the main control valve piston 76 is about a factor of 2 larger than the upper control surface 97 exposed to the accumulator pressure p s , which corresponds to the cross-sectional area A, of the actuating plunger 89, so that a control pressure p x coupled into the lower control chamber a value p s • AJA is sufficient to push the main control valve piston 76 into the upper end position shown in FIG. 3c. If, on the other hand, the lower control chamber 82 is relieved of pressure, the main control valve piston 76 reaches the lower end position shown in FIG. 3a, in which it is supported with the annular control surface 92 on a conical counter surface 98 of the lower housing end part 78.
• the upper end position of the main control valve piston 76 shown in FIG. 3c is assigned to the feed and cutting operation of the sheet metal shears 10, in which the upper knife 17 moves towards the sheet metal web 11 and cuts it.
• the lower end position of the main control valve piston 76 shown in FIG. 3a is assigned to the upward retraction operation of the upper knife 17, in which the piston rods 44 and 46 of the drive hydraulic cylinders 27 and 28 are retracted until finally an upper dead center of the position of the upper knife 17 is reached, to which the central position of the main control valve piston 76 shown in FIG. 3b is assigned.
• the main control valve piston 76 In the upper end position of the main control valve piston 76 is an upper connection space 99 of the main control valve 73, which is in constant communication with the unpressurized reservoir 66 of the pressure supply unit 62 via a T supply connection 101, through the upper end flange 91 of the main control valve piston 76 delimited pressure-tight against an A-ring space 102 which communicates with the A-consumer port 103 to which the bottom-side drive pressure chamber 49 of the larger drive hydraulic cylinder 27 is connected.
• the A-ring space 102 In the upper end position of the main control valve piston 76, the A-ring space 102, with the largest possible overflow cross section, communicates with a P-ring space 106 arranged between the latter and a B-ring space 104 of the main control valve 73, which in turn is connected to the P supply connection 107 of the Main control valve 73 is in permanently communicating connection, to which the P-pressure outlet 109 of the constant pump 63 of the pressure supply unit 62 is connected via an outlet check valve 108 (FIG. 2).
• the B-ring space 104 which in turn is between the P-ring space 106 and a storage ring space 111 of the main control valve 73, which has a storage connection
• a B blocking flange 114 which, in the upper end position of the main control valve piston 76, in a central section 116 extending between the P-ring space 106 and the B-ring space 104 ! of the axially continuous valve bore of the central housing block 81, designated overall by 116, which extends between the upper housing end part 79 and the lower housing end part 78.
• the accumulator annulus 111 is also blocked off from the B annulus 104, the respective blocking being mediated by a accumulator blocking flange 117 of the main control valve piston 76, which in the upper end position of the main control valve piston 76 is in a lower intermediate section 116 2 of the central housing bore 116 is immersed, which extends between the B-ring space 104 and the storage ring space 111.
• the storage annulus 111 is connected via a "radial" supply channel 112 '(FIG. 3c) to the storage port 112 and is via a control channel 118 which extends approximately axially through the central housing block 81 and which, for the sake of simplicity of illustration, is only shown in FIGS 3b is shown schematically, and a connection channel 118 'of the upper housing end part 79 which continues this is kept in constantly communicating connection with the upper control chamber 87 of the valve housing 77, so that the accumulator pressure in accordance with the relationship (1) determines the restoring force against which the valve piston 76 can be "shifted upward” by coupling the control pressure into the lower control chamber 82.
• the piston 76 of the main control valve has an A blocking flange 119 which, in the functional position I of the main control valve 73 associated with the retracting operation of the cutting knife 17, which is shown in FIG A-ring space 102 with the upper intermediate section 116 3 connecting the P-ring space 106 of the axially continuous valve bore 116 is immersed, thereby sealing off the A-ring space 102 against the P-ring space 106 in a pressure-tight manner.
• the A-blocking flange 119 is completely in the A-ring space 102, the axial extent of which is greater than the axial thickness of the A. Locking flange 119, immersed, so that in this functional position II communicating connecting tion between the P-ring space 106 and the A-ring space 102, which is blocked in this functional position against the unpressurized T-ring space 99 in that the upper end flange 91 of the piston 76 is immersed in the upper end portion 116 4 of the central valve housing bore 116 , which extends between the T-connection space 99 and the A-ring space 102.
• the storage blocking flange 117 is completely immersed in the lower end section 116 5 of the continuous valve bore 116, in which the lower piston end section 93 is arranged so that it can be moved in a pressure-tight manner.
• the storage locking flange 117 of the valve piston 76 is immersed in the lower intermediate section 116 2 of the central valve bore 116 and locks the storage annulus 111 from the bottom "from below" - Annulus 104 from.
• the A-ring space 102, the P-ring space 106, the B-ring space 104 and the storage ring space 111 are formed on the house side by the centrally continuous housing bore 116 in sections, radially widening ring grooves, the groove cheeks of which form circular control edges 12 ⁇ to 121 8 on the housing side, extend radially to the central longitudinal axis 74 of the central valve bore 116.
• Piston- side control edges 122 ⁇ to 122 8 through their negative or positive overlaps with the corresponding housing-side control edges 121, to 121 8, the valve-path combinations used for the respective function are released or the paths that are not used are blocked off, are peripheral Edge edges of the piston flanges 91, 119, 114 and 117 are formed, by means of which their radial flange surfaces are connected to the Connect cylindrical sealing surfaces with which the piston flanges can be slid in a pressure-tight manner in the assigned sections of the central valve bore 116.
• the “lower” control edge 122 2 of the upper end flange 91 facing the A-ring space, the “upper” control edge 122 3 of the A-locking flange 119 facing the upper end flange 91 are the upper, the control edge 122 5 of the B locking flange 114 facing the P-ring space 106 and the lower control edge 122 8 of the storage locking flange 117 facing the cylindrical end section 93 of the valve piston 77 each as a circular edge lying in a plane perpendicular to the central longitudinal axis 74 of the main control valve 73 formed, in whose arrangement aligned with the corresponding control edge on the housing, the 0 overlap is given; the course of the upper control edge 122 facing the upper connection space 99 of the main control valve 73, the course of the lower control edge 122 4 of the A-blocking flange 119 facing the P-ring space 106, the course of the lower control edge facing the storage ring space 111 122 6
• the main control valve 73 assumes the functional position I shown in FIG. 3a; this is the case when the pilot valve 83 is switched to its basic position 0 and the changeover valve 84 is switched to its switching position I by energizing its control magnet 124.
• the x control connection 86 of the main control valve 73 is then connected via the changeover valve 84 to the control outlet 126 of the pilot valve 83, which in the basic position 0 of the pilot valve 83 is connected to the pressureless reservoir 66 of the pressure supply unit 62, against the P pressure supply connection 127 of the piiotventis 83 but is cordoned off.
• the B-ring space 104 communicates with the P-ring space 106, into which the outlet pressure of the constant pump 69 is coupled, with a large overflow cross section.
• the A-ring space 102 is "already” blocked off from the upper, unpressurized connection space 99 with O overlap of the upper housing-side control edge 12 ⁇ and the upper control edge 122 ⁇ , which is formed by a flange notch, and the A- Annulus 102 is "still” with 0- Blocked overlap of its lower control edge 121 2 on the housing side with the lower control edge 122 4 of the A locking flange 119 formed by a flange notch 123 against the P-ring space 106.
• Deflection range which is limited at the bottom by the fact that the B-blocking flange 114 blocks the B-ring space 104 against the storage ring space 111 and at the top in that the B-blocking flange 114 blocks the P-ring space 106 against the B-ring space 104 and / or the storage blocking flange 117 shuts off the storage annulus 111 against the B-annulus 104, communicating connection between the P-annulus 106 which the constant pump 61 is connected and the storage annulus 111 to which the pressure accumulator 88 is connected, so that the pressure accumulator 88 can be charged within this stroke range.
• a storage charging valve arrangement designated overall by 131, is provided, with the function of charging the pressure accumulator 88 by means of the constant pump 63 as soon as the storage pressure falls below a lower limit value and as soon as the pressure accumulator 88 is charged again to an upper limit value to switch the constant pump to circulating operation, which is linked to a low power consumption.
• the accumulator loading valve arrangement 131 comprises a pressure-controlled, as a 2/2-way valve changeover valve 132, which on the one hand by a prestressed valve spring 133 with a minimum force and on the other hand by a pressure coupled into a first control chamber 134 into its blocking basic position is pushed.
• the pressure outlet 109 of the constant pump 63 by means of which the pressure accumulator 88 can be charged via the outlet check valve 108, is connected on the one hand via a throttle 137 to the first control chamber 134 and on the other hand "directly" to a second control chamber 138 of the changeover valve 132, by applying the pressure to the outlet pressure of the constant pump 63, a force results which forces the valve piston of the changeover valve 32 into its flow position I, in which the pressure outlet 109 of the constant pump 63 is connected to a return line 139 leading directly to the reservoir 66 and the pump 63 works in circulation.
• the end faces, not shown, which form the axially movable boundaries of the control chambers 134 and 138 and which are represented by the 2/2-valve symbol Sent valve pistons are matched to one another in such a way that the amount f, the piston end face forming the axially movable boundary of the first control chamber 134, is considerably larger than the amount f 2 , the piston forming the axially movable boundary of the second control chamber 138 of the changeover valve 132 -End end face, a typical value of the area ratio f, / f 2 being around 1.4.
• the accumulator loading valve arrangement 131 comprises a pressure valve 141, which is actuated with the pressure currently prevailing in the accumulator 88 and serves as a pilot valve for the changeover valve 132, which functionally is a 2/2 valve which, when the accumulator pressure a maximum value of e.g. 70 bar, reaches its flow position, in which the control chamber 134 of the changeover valve 132, which is limited in its large movable area, is connected to a relief control path 142, and that when the storage pressure falls below its lower limit value, which is e.g. is 10% lower than the upper limit, falls back into its blocking basic position, in which the first control chamber 134 is again blocked off against the relief control path 142.
• a pressure valve 141 which is actuated with the pressure currently prevailing in the accumulator 88 and serves as a pilot valve for the changeover valve 132, which functionally is a 2/2 valve which, when the accumulator pressure a maximum value of e.g. 70 bar, reaches its flow
• the relief control path 142 is guided via a mechanically controlled auxiliary valve 143, the piston 143 'of which, represented by a 2/3-way symbol, on both sides of a central position, consists in the communicating connection of the relief control path 142 with the unpressurized reservoir 66 of the pressure supply unit 62 , each has a blocking position I or II, in which the relief control path 142 is blocked.
• the piston 143 'of the auxiliary valve 143 is positively coupled to the piston 76 of the main control valve 73 in such a way that the auxiliary valve 143 assumes its open central position 0 when the piston 76 of the main control valve 73 also assumes a position within the stroke range suitable for storage charging and outside of this stroke range, ie in for the downward feed and cutting operation and in the functional positions of the main control valve piston 76 used for the upward retraction operation of the upper knife 17 assume the respective blocking position I or II.
• the pilot valve 141 is in its blocking basic position, since the accumulator pressure is far from sufficient to open the pilot valve 141.
• the auxiliary valve 143 assumes its flow position 0.
• the constant pump 63 charges the pressure accumulator 88 via the output check valve 108, the output pressure of the constant pump 63 constantly increasing.
• the changeover valve 132 remains in its blocking basic position, since the pressure coupled into the control chamber 134, which is limited to a large area, is at most slightly lower than the output pressure of the constant pump coupled into the control chamber 138, which is limited to a small area, since the pressure between the control chamber 134 which is limited to a large area and the pressure output 136 of the constant pump lying throttle in this operating state can not cause any significant pressure drop, but the area ratio f1 / f2 ensures that the changeover valve 132 remains in its blocking position.
• the pilot valve 141 opens, so that now a hydraulic oil flow from the pressure output 109 of the constant pump 63 via the throttle 137, the open pilot valve 141 and through that Auxiliary valve 143 released relief control path 142 can flow to the unpressurized reservoir 66, the output pressure of the pump essentially dropping via the throttle 137, with the result that even in the first control chamber 134, which is limited in area, there is only a pressure which due to the flow resistance, which can be assumed to be low, of the relief flow path downstream of the throttle 137, which includes the pilot valve 141, the relief control path 142 and the auxiliary valve 143, is only slightly above the ambient pressure level at which the reservoir 66 is located .
• the output pressure of the constant pump 63 which is coupled into the small-area, second control chamber 138, also drops below the amount of the pressure prevailing in the accumulator 88, but, provided that the bypass throttle 137 is suitably designed, remains sufficiently high that the changeover valve is switched to its flow position I, in which a far predominant part of the hydraulic oil output flow of the constant pump 63 flows through the changeover valve 132 and the return line 139 back to the reservoir 66, that is, the constant pump 63 operates with little power loss in circulation mode.
• the auxiliary valve 143 which assumes its blocking position I or II in the upward movement phases and in the downward movement phases of the upper knife 17 and thereby prevents a storage charging operation in these movement phases, so that the entire oil quantity conveyed by the constant pump 63 is used for the movement control the drive hydraulic cylinder 27 and 28 is available, is integrated in the main control valve 73.
• the relief control path 142 (FIG. 4)
• Annular groove 144 is provided, which communicates with an x control connection 146 of the central housing block 81 of the valve housing 77.
• the lower piston section 93 which is displaceably guided in a pressure-tight manner in the lower end section 116 5 of the through valve bore 116 and is offset from the storage blocking flange 117 by a piston rod-shaped section 145 of smaller diameter, is provided with a “radial” window opening 147, which in the illustrated example with a central piston bore 148, which ends within the lower piston section 93 and axially penetrates the main control valve piston 76, including its upper end flange 91, and which in turn is in any of the possible piston positions with the upper connection chamber 99 of the main control valve 73 communicates, which is "directly” connected to the unpressurized reservoir 66 of the pressure supply unit 62 via the T supply connection 101 of the main control valve 73.
• the window opening 147 of the piston is arranged significantly below the x ring groove 144, that is, there is positive overlap between the lower, housing-side control edge 161 of the ring groove 144 and the upper control edge 149 of the piston window 147 which is parallel thereto (FIG.
• the window opening 147 of the main control valve piston 76 is arranged at a significant distance from the x annular groove 144 above it, i.e.
• piston-side control edge 151 is given, so that from each of the two end positions As seen from I and II, an upward or downward minimum stroke of the main control valve piston 76 is required in order to bring the window opening 147 into communicating connection with the x annular groove 144, ie communicating connection between the unpressurized reservoir 66 and the outlet 162 of the pilot valve 141 of the accumulator loading valve assembly 131 as required for the accumulator loading operation.
• the stroke range within which a store loading operation is possible ie the auxiliary valve 143 assumes its open position 0, thus corresponds to the amount of the axial clear width of the window opening 147 plus the clear width w of the x annular groove 144 and has an explanation for that selected design of the main control valve 73 and the auxiliary valve 143, which corresponds to the scale representations of FIGS. 3a, 3b and 3c, a value of 8 mm, the axial clear width of the window opening 147 corresponding to the axial clear width w of the x r ring groove 144.
• the total stroke of the main control valve piston 76 which is composed of the lower partial stroke Al ⁇ leading from the lower end position to the middle position and the upper partial stroke ⁇ h 2 leading from the middle position to the upper end position, has a value of 11.5 mm, whereby the "lower" partial stroke Al ⁇ in the exemplary embodiment chosen for explanation is 7mm.
• the annular control surface 92 of the main control valve piston 76, on which the control pressure p x which can be coupled into the lower control chamber 82 acts, has an amount of 0.53 cm 2 in the exemplary embodiment selected for the explanation, and the effective cross-sectional area of the actuating plunger 89, to which the valve is permanently connected the upper control chamber 87 of the main control valve 73 acts as a storage pressure, has an amount of 0.28 cm 2 .
• the hold-down devices 29 are relieved of pressure, their drive pressure spaces 34 via a "throttled" flow channel 163 of an outlet valve 164 and one in the basic position
• the inlet valve 167 for the explanation of which reference is also made to FIG. 5a, is designed as a pressure-controlled 2/2-way valve, on the piston designated by 171 the force of a weakly preloaded valve spring 172 acting on the piston 171 in urges its "upper" end position, corresponding to the blocking state of valve 167, in which a storage connection 173 of valve 167 is blocked against its hold-down connection 174.
• the valve housing 176 has two interlocking over a radial inner shoulder 177 on continuous, with respect to the central longitudinal axis 178 coaxial bore stages d 179, and 181 of different diameters, respectively d 2, in which the piston 171, which in turn is formed as a stepped piston, with piston stages 182 or 183 corresponding to different diameters d and d 2 is guided in a pressure-tight manner.
• the larger diameter piston stage 183 forms the axially movable boundary of a "lower", pump-side control chamber 187, which leads via an inlet check valve 188 and a throttle orifice 189 to the outlet check valve 108 of the pressure supply unit 62 to the P-supply connection 107 of the main control valve P-pressure supply line 191 is connected, the throttle orifice 189 being arranged between the P-pressure supply line 191 and the input check valve 188.
• the valve housing 176 has a cross-hole tion 192, which opens radially on the outside into an annular space 193 of the valve housing, with which the hold-down connection 174 is in communicating connection.
• a "lower" annular space 194 of variable axial expansion is also communicatively connected to the hold-down connection 174 or the transverse bore 192, which is axially movably limited by the flange-shaped piston stage 183 of the larger diameter d 2 , with the flange-shaped piston stage 183 and the elongated cylindrical piston stage 182 of the smaller diameter d a stop stage 196 is provided, by its abutment on the annular shoulder 177 of the housing the upper end position of the piston 171 is marked, in which the valve piston 171 so far in the upper part of the memory-side control chamber 186 fixed to the housing limiting bore stage 179 is immersed that the upper control chamber 186 is hermetically sealed against the transverse bore 192.
• the outlet valve 164 is provided for the purpose of enabling the fastest possible pressure relief of the drive pressure spaces 34 of the hold-down devices 29, if these have to be released after executing a cutting stroke of the upper knife 17 by retracting the piston rods 39 of the hold-down devices.
• the outlet valve 164 as can be seen directly from its detailed illustration in FIG. 5b, is essentially identical in construction to the inlet valve 167 (FIG. 5a) and differs from this only in that its piston 171 'has an axially continuous central bore 163 which, in the illustrated upper end position of the valve piston 171 ', communicatively connects the upper control chamber 186' with the lower control chamber 187 'of the exhaust valve 164.
• the central bore 163 is provided at its one end, as shown in the upper end, with a throttle diaphragm 198 which essentially determines the flow resistance of the flow channel extending between the upper control chamber 186 'and the lower control chamber 187'.
• the outlet valve 164 is inserted into the electrohydraulic control unit 72 as follows:
• the valve inlet 173 'of the outlet valve 164 opening into the smaller bore step 179 is "directly” connected to the drive pressure chambers 34 of the hold-down devices 29.
• the valve connection 174 'which constantly communicates with the annular space 194 of the clear cross-sectional area F 3 forms the outlet of the outlet valve 164, which is connected "directly” to the unpressurized reservoir 66 of the pressure supply unit 62 on the one hand via a return line 201 and on the other hand via a throttle orifice 202 a second control connection 203 of the pilot valve 83 is connected, both in the spring-centered basic position 0 of the pilot valve 83 and in its function position I assigned to the downward feed and cutting operation, via an additional flow path 204 with the unpressurized reservoir 66 of the pressure supply unit 62 is connected.
• the lower control chamber 187 'of the exhaust valve 164 is in communication with the x control outlet 126 of
• a pressure reducing valve 207 of the electro-hydraulic control unit 72 is connected between the input check valve 188, via which the pump-side control chamber 187 of the inlet valve 167 is connected to the P pressure supply line 191, and the P pressure supply connection 127 127 of the pilot valve 83 resulting pressure is limited to a value that can be significantly higher than the outlet pressure of the accumulator 88.
• the area changeover valve is designed as a pressure-controlled 3/2-way valve, which is urged into its basic position 0 by the pretensioning of a valve spring 210, in which a flow path 211 of the area changeover valve 209 is released, via which the B consumer connection 113 of the main control valve 73, to which the rod-side drive pressure chamber of the smaller hydraulic cylinder 28 is connected, to which the P supply connection 107 is connected.
• the force acting in the same direction as the valve spring 210 is that which is represented by the pressure coupling into a first control chamber 212 of the surface switching valve 209, which is represented by the 3/2-way valve symbol
• Piston is exercised.
• This first control chamber 212 is connected via a control line 213 to the B consumer port 113 of the main control valve 73.
• a second control chamber 214 of the surface switching valve 209 which is connected via a further control line 216 to the A consumer connection 103 of the main control valve 73
• the axially movable limitation of the second control chamber 214 forming end face of the valve piston is greater in amount than that end face which forms the axially movable boundary of the first control chamber 212
• the valve piston of the surface switching valve 209 can be moved into the switching position I of the surface switching valve, in which a flow path 217 is released, which opens the B- Consumer connection 113 "directly" connects to the unpressurized reservoir 66 of the pressure supply unit 62.
• the surface switch valve 209 is designed in coordination with the drive hydraulic cylinders 27 and 28 so that when a threshold value p us of the operating pressure coupled into the bottom drive pressure chamber 49 of the larger drive hydraulic cylinder 27 is reached from its basic position 0, in which the rod-side An - Drive pressure chamber 53 of the smaller drive hydro cylinder is connected to the p-supply connection 107 of the main control valve, reaches its switching position I, in which the rod-side drive pressure chamber 53 of the smaller drive hydro cylinder 28 is connected to the unpressurized reservoir 66; The surface switching valve 209 is then only switched back to its basic position when the pressure prevailing in the drive pressure space 49 on the bottom of the larger drive cylinder falls below a threshold value p R , which is due to the relationship
• a 3 denotes the annular area of its piston 43 exposed to the pressure in the rod-side drive pressure chamber 53 of the smaller drive hydro-cylinder 28, the circular area of its piston 42 exposed to the pressure in the bottom-side drive pressure chamber 49 of the larger drive cylinder 27, and a denotes a constant that preferably has a value around 0.1. This ensures that the surface Chenumschaltventil 209 maintains its switching position I as long as there is an increased power requirement.
• the area switching valve 209 can also be designed as an electrically controllable valve which can be controlled as a function of sensed values of the operating pressure, a typical threshold value p R of the operating pressure at which the area switching valve is in its Switching position I switches, is about 220bar.
• the upper knife 17 is in its regulated upper end position, ie, it varies within a slight range of fluctuation.
• the hold-down devices 29 are retracted.
• the inlet valve 167 is blocked since the outlet pressure of the accumulator 88 is coupled into its lower control chamber 187 via the main control valve 73, so that the valve spring 172 is able to hold the inlet valve 167 in its blocked position.
• the exhaust valve 164 is also locked because both its upper and lower control chambers are at the pressure level of the reservoir 66 and therefore the closing force of the valve spring 172 is sufficient, the exhaust valve 164 to keep in its locked position.
• the pilot valve 83 assumes its basic position, which is centered by two valve springs 218 and 219 which act in the opposite direction and which is assigned to the upward travel operation of the upper knife 17 and the accumulator loading operation in the TDC position.
• the pilot valve 83 which is designed as an electrically controllable solenoid valve, is switched to its switching position I, in which its P pressure supply connection 127 communicates with its x control output 126, the flow path 221 thereby released is, however, blocked off from a likewise released relief flow path 222 which, also in the functional position I of the pilot valve 83, the connection between the unpressurized reservoir 66 and which corresponds to the relief path 166, which is released in the basic position 0 of the pilot valve 83 the return line 201 or the outlet valve connection 174 'of the outlet valve 164.
• the lower control chamber 187 of the inlet valve 167 has a communicating connection with the lower control chamber 187 'of the outlet valve 164, which via the throttle orifice 198 of the Piston 171 'is in communication with the drive pressure chambers 34 of the hold-down device 29, with the result that a pressure drop occurs in the lower control chamber 187 of the inlet valve 167 and this reaches its open position, in the hydraulic oil from the reservoir 88 via the flows from the storage connection 173 to the hold-down connection 174 leading through the pressure relief flow path of large cross section.
• Hydraulic oil displaced from the rod-side drive pressure chamber 53 of the smaller drive hydraulic cylinder 28 flows as long as the surface changeover valve 209 is in its basic position 0, “back” to the P supply connection 107 of the main control valve 73 and adds up to the one supplied by the constant pump 63 Hydraulic oil flow, with the result that the two drive hydraulic cylinders 27 and 28 work in an "Eir" feed mode, which leads to a rapid approach of the upper knife 17 to the sheet metal web 11.
• the pressure in the drive pressure chambers of the drive hydraulic cylinders 27 and 28 increases to the extent that the cutting force to be cut to cut the sheet metal web 11 increases. If a pressure of e.g. Exceeded 220bar, the pressure-controlled surface changeover valve 209 goes into its switching position I, in which the rod-side drive pressure chamber 53 of the smaller hydraulic drive cylinder 28 is connected to the unpressurized reservoir 66 via the flow path 217 of the surface changeover valve 209 that is now released.
• a pressure of e.g. Exceeded 220bar the pressure-controlled surface changeover valve 209 goes into its switching position I, in which the rod-side drive pressure chamber 53 of the smaller hydraulic drive cylinder 28 is connected to the unpressurized reservoir 66 via the flow path 217 of the surface changeover valve 209 that is now released.
• the two drive hydraulic cylinders 27 and 28 now operate in a "load" feed mode, in which the feed force is increased, but the feed speed decreases, since only the amount of hydraulic oil delivered by the constant pump 63 via the A consumer connection 103 to the upper one Drive pressure chamber 49 of the larger drive hydraulic cylinder 27 is promoted.
• the pilot valve 83 is switched back to its basic position 0, for example controlled by the output signal of a UT switch 225 responding to this lower end position of the upper knife 17.
• a pressure relief of the lower control chamber 82 of the main control valve 73 occurs, via the changeover valve 84 remaining in its switching position I, the valve piston 76 of which is thereby pushed into its lower end position, and also a pressure relief of the lower control chamber 187 'of the exhaust valve 164, the piston 171 'of which, due to the pressure drop across its throttle orifice 198, is displaced downwards, with the result that the flow path which conveys the pressure relief of the hold-down devices and corresponds to the open position of the outlet valve 164, which leads directly to the unpressurized reservoir 66 , is released and the hold-down 29 quickly lift off the sheet metal 11.
• the pilot valve 83 is designed as a 3-position valve, which can be switched from the spring-centered basic position 0 against the action of one of the two valve springs 218 and 219 to the functional positions I and II by alternative excitation of its control magnets.
• the function position II (not yet explained), two flow paths 226 and 227 of the pilot valve 83 are released, one flow path 227 connecting the pressure supply connection 127 of the pilot valve 83 to its second control connection 203, and the other flow path 226 connecting the x control output 126 of the pilot valve 83 connects to its T-return port 208.
• This functional position II of the pilot valve 83 is assigned to a "slow" lowering operation of the upper knife 17, in which the constant pump is switched off and the surface switching valve 209 is in its basic position 0.
• hydraulic oil can flow from the pressure chamber 53 on the rod side of the smaller hydraulic cylinder 28 via the open flow path 211 of the area changeover valve 209, the throttle orifice 189, the input check valve
• the setting of the small cutting angle ⁇ which includes the cutting edge 18 of the upper knife 17 with the sheet metal plane, is carried out by actuating the small drive hydraulic cylinder 28 in the sense of raising or lowering the end of the movement coupling which is coupled to the piston rod 46 of this hydraulic cylinder Upper knife, ie by pivoting about the hinge axis 58 about which the upper knife carrier 57 can be swiveled up and down in the area of the larger drive hydraulic cylinder 27, the angle setting being made in the TDC position of the upper knife 17 with which the regulated copying position of the main control valve 73 is linked .
• an angle control valve 228 of the electro-hydraulic control unit 72 is provided, which is designed as an electrically controllable 4/3-way solenoid valve, which has a basic position 0 centered by valve springs 229 and 231 and alternative switching positions adjustable by individual excitation of two control windings of a control magnet system gen I and II has, which are assigned to the lowering or retracting operation of the piston 43 of the smaller hydraulic cylinder 28.
• the angle control valve 228 has a p-supply connection 232 connected to the rod-side drive pressure chamber 53 of the smaller drive hydraulic cylinder and thus also to the B-consumer connection 113 of the main control valve 73, and a T-return connection connected to the unpressurized reservoir 66 of the pressure supply unit 62 233, a check valve 234 that can be unlocked via a pressure control and a throttle orifice 236 connected to the bottom-side drive pressure chamber 51 of the smaller hydraulic drive cylinder 28, and a control outlet 238 that is connected to a control input 239 of the unlockable check valve 234.
• the P supply connection 232 is blocked off from the consumer connection 237, but this is connected to the T return connection 233, with which the control output 238 of the angle control valve 228 also communicates in the basic position of the angle control valve connected is.
• the check valve is blocked.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shearing Machines (AREA)
• Drilling Tools (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7897023

Family Applications (1)

Country Status (4)

Families Citing this family (16)

Family Cites Families (5)

• 1999
  • 1999-02-10 DE DE19905475A patent/DE19905475A1/de not_active Withdrawn
• 2000
  • 2000-02-10 AT AT00906317T patent/ATE228412T1/de not_active IP Right Cessation
  • 2000-02-10 WO PCT/EP2000/001092 patent/WO2000051770A1/fr active IP Right Grant
  • 2000-02-10 DE DE50000819T patent/DE50000819D1/de not_active Expired - Fee Related
  • 2000-02-10 EP EP00906317A patent/EP1150794B1/fr not_active Expired - Lifetime

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events